Composition to provide a layer with uniform etch characteristics

ABSTRACT

The present invention includes a composition to form a layer on a substrate having uniform etch characteristics. To that end, the composition has a plurality of components, a subset of which has substantially similar rates of evaporation for an interval of time.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The United States government has a paid-up license in this invention andthe right in limited circumstance to require the patent owner to licenseothers on reasonable terms as provided by the terms of 70NANB4H3012awarded by National Institute of Standards (NIST) ATP Award.

CO-PENDING APPLICATION

This application relates to co-pending U.S. patent application Ser. No.10/919,224 entitled “Method to Provide a Layer with Uniform EtchCharacteristics,” naming inventors Frank Y. Xu, et al, filed on Aug. 16,2004.

BACKGROUND OF THE INVENTION

The field of invention relates generally to micro-fabrication ofstructures. More particularly, the present invention is directed tomethods and the imprinting materials to form layers having uniform etchcharacteristics.

Micro-fabrication involves the fabrication of very small structures,e.g., having features on the order of micro-meters or smaller. One areain which micro-fabrication has had a sizeable impact is in theprocessing of integrated circuits. As the semiconductor processingindustry continues to strive for larger production yields whileincreasing the circuits per unit area formed on a substrate,micro-fabrication becomes increasingly important. Micro-fabricationprovides greater process control while allowing increased reduction ofthe minimum feature dimension of the structures formed. Other areas ofdevelopment in which micro-fabrication has been employed includebiotechnology, optical technology, mechanical systems and the like.

An exemplary micro-fabrication technique is shown in U.S. Pat. No.6,334,960 to Willson et al. Willson et al. disclose a method of forminga relief image in a structure. The method includes providing a substratehaving a transfer layer. The transfer layer is covered with apolymerizable fluid composition. An imprint device makes mechanicalcontact with the polymerizable fluid. The imprint device includes arelief structure formed from lands and grooves. The polymerizable fluidcomposition fills the relief structure with the thickness of thepolymerizable fluid in superimposition with the lands defining aresidual thickness. The polymerizable fluid composition is thensubjected to conditions to solidify and polymerize the same, forming asolidified polymeric layer on the transfer layer that contains a reliefstructure complimentary to that of the imprint device. The imprintdevice is then separated from the solidified polymeric layer such that areplica of the relief structure in the imprint device is formed in thesolidified polymeric layer. The transfer layer and the solidifiedpolymeric layer are subjected to an environment to selectively etch thetransfer layer relative to the solidified polymeric layer such that arelief image is formed in the transfer layer. Thereafter, conventionaletching processes may be employed to transfer the pattern of the reliefstructure into the substrate.

Conventional etching processes form desired patterns in a layeremploying an appropriate mask, e.g. a photoresist mask. The mask istypically deposited on the layer and patterned, forming a patternedmask. The patterned mask is then exposed to an etchant, such as ions ina dry etch process or a liquid acid in a wet etch technique, to removeportions of the layer exposed through the patterned mask.

A desired characteristic of any etch process is to obtain a uniform etchrate over the surface being etched. To that end, the prior art isreplete with attempts to control the etch rate during an etchingprocess. For example, U.S. Pat. No. 6,132,632 to Haney , et al.,discloses a method and apparatus for achieving etch rate uniformity in areactive ion etcher. The reactive ion etcher generates a plasma within avacuum chamber for etching a substrate disposed at a cathode of areactor can within the chamber wherein the plasma emanates from a topplate of the reactor can, and is influenced by localized magnetic fieldsfor locally controlling etch rates across the cathode to produce auniform etch rate distribution across the cathode as a result of thelocalized magnetic field. The magnet array may be disposed between thetop plate and the vacuum chamber for providing the localized magneticfields. The magnet array includes a plurality of individual magnets anda grid plate for holding the individual magnets in position.

U.S. Pat. No. 6,344,105 to Daugherty et al. discloses a method andapparatus for ion-assisted etch processing in a plasma processingsystem. In accordance with various aspects of the invention, an elevatededge ring, a grooved edge ring, and a RF coupled edge ring aredisclosed. The invention operates to improve etch rate uniformity acrossa substrate (wafer). Etch rate uniformity improvement provided by theinvention not only improves fabrication yields but also is costefficient and does not risk particulate and/or heavy metalcontamination.

U.S. Pat. No. 6,576,408 to Meador et al. discloses anti-reflectivecoating compositions having improved etch rates. The compositions areprepared from certain acrylic polymers and copolymers, such as, glycidylmethacrylate reacted with non-polycyclic carboxylic acid dyes andnon-polycyclic phenolic dyes, all light absorbing at a wavelength of 193nm.

There is a need, therefore, to provide etching techniques with improvedcontrol of the etch rate of the imprinting material undergoingprocessing.

SUMMARY OF THE INVENTION

The present invention includes a flowable composition having a pluralityof components, a subset of which has a substantially identical rate ofevaporation for an interval of time. The present invention is based uponthe discovery that etch non-uniformity in a layer that is formed bysolidification of a deposited liquid is a function of the relative ratesof evaporation of the components that form the layer. These and otherembodiments are discussed more fully below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a lithographic system in accordance withthe present invention;

FIG. 2 is a simplified elevation view of a lithographic system, shown inFIG. 1, employed to create a patterned imprinting layer in accordancewith one embodiment of the present invention;

FIG. 3 is a simplified elevation view of an imprint device spaced-apartfrom the patterned imprinting layer, shown in FIG. 1, after patterningin accordance with the present invention;

FIG. 4 is a top-down view of a region of the substrate, shown in FIG. 2,upon which patterning occurs, employing a pattern of droplets ofpolymerizable fluid disposed thereon;

FIG. 5 is a cross-sectional view of a layer, formed from a prior artpolymerizable of the imprinting material, deposited on a substrate;

FIG. 6 is a cross-sectional view of the layer shown in FIG. 5 afterbeing subjected to an RIE etch process, in accordance with the priorart;

FIG. 7 is a graph showing the rate of evaporation of the differingcomponents of a silicon-containing polymerizable of the imprintingmaterial in accordance with the present invention;

FIG. 8 is a cross-section view showing a release layer and a primerlayer that may be employed in accordance with the present invention;

FIG. 9 is a cross-section view showing a release layer applied to aplanarization mold shown in FIG. 8; and

FIG. 10 is a cross-section view showing formation of layer upon asubstrate in accordance with an alternate embodiment of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 depicts a lithographic system 10 in accordance with oneembodiment of the present invention that includes a pair of spaced-apartbridge supports 12 having a bridge 14 and a stage support 16 extendingtherebetween. Bridge 14 and stage support 16 are spaced-apart. Coupledto bridge 14 is an imprint head 18, which extends from bridge 14 towardstage support 16. Disposed upon stage support 16 to face imprint head 18is a motion stage 20. Motion stage 20 is configured to move with respectto stage support 16 along X and Y axes and may provide movement alongthe Z axis as well. A radiation source 22 is coupled to system 10 toimpinge actinic radiation upon motion stage 20. As shown, radiationsource 22 is coupled to bridge 14 and includes a power generator 23connected to radiation source 22.

Referring to both FIGS. 1 and 2, connected to imprint head 18 is atemplate 24 having a patterned mold 26 thereon. Patterned mold 26includes a plurality of features defined by a plurality of spaced-apartrecesses 28 and projections 30. Projections 30 have a width W₁, andrecesses 28 have a width W₂, both of which are measured in a directionthat extends transversely to the Z axis. The plurality of featuresdefines an original pattern that forms the basis of a pattern to betransferred into a substrate 32 positioned on motion stage 20. To thatend, imprint head 18 is adapted to move along the Z axis and vary adistance “d” between patterned mold 26 and substrate 32. Alternatively,or in conjunction with imprint head 18, motion stage 20 may movetemplate 24 along the Z-axis. In this manner, the features on patternedmold 26 may be imprinted into a flowable region of substrate 32,discussed more fully below. Radiation source 22 is located so thatpatterned mold 26 is positioned between radiation source 22 andsubstrate 32, with actinic radiation generated by radiation source 22propagating through patterned mold 26. As a result, it is desired thatpatterned mold 26 be fabricated from material that is substantiallytransparent to the actinic radiation. Exemplary materials from whichpatterned mold 26 may be fabricated include fused-silica, quartz,silicon, organic polymers, siloxane polymers, borosilicate glass,fluorocarbon polymers, metal, and combinations of the above dependentupon the actinic radiation employed. An exemplary system is availableunder the trade name IMPRIO 100™ from Molecular Imprints, Inc. having aplace of business at 1807-C Braker Lane, Suite 100, Austin, Tex. 78758.The system description for the IMPRIO 100™ is available atwww.molecularimprints.com and is incorporated herein by reference.

Referring to FIG. 2, a flowable region, such as an imprinting layer 34,is formed on a portion of surface 36 that presents a substantiallysmooth, if not planar, profile of a surface facing template 24. In oneembodiment of the present invention, the flowable region is deposited asa plurality of spaced-apart discrete droplets 38 of imprinting materialon substrate 32, discussed more fully below. The imprinting material maybe selectively polymerized and cross-linked to record an inverse of theoriginal pattern therein, defining a recorded pattern. The plurality offeatures on patterned mold 26 are shown as recesses 22 extending along adirection parallel to projections 30 that provide a cross-section ofpatterned mold 26 with a shape of a battlement. However, recesses 28 andprojections 30 may correspond to virtually any feature required tocreate an integrated circuit and may be as small as a few tenths of ananometer.

Referring to FIGS. 2 and 3, the pattern recorded in imprinting layer 34is produced, in part, by mechanical contact with patterned mold 26. Tothat end, the distance “d” is reduced to allow imprinting layer 34 tocome into mechanical contact with patterned mold 26, spreading droplets38 so as to form imprinting layer 34 with a contiguous formation of theimprinting material over surface 36. In one embodiment, distance “d” isreduced to allow sub-portions 46 of imprinting layer 34 to ingress intoand fill recesses 28.

In the present embodiment, sub-portions 48 of imprinting layer 34 insuperimposition with projections 30 remain after the desired, usuallyminimum distance “d”, has been reached, leaving sub-portions 46 with athickness t₁, and sub-portions 48 with a thickness, t₂. Thickness t₂ isreferred to as a residual thickness. Thicknesses “t₁” and “t₂” may beany thickness desired, dependent upon the application. The total volumecontained in droplets 38 may be such so as to minimize, or avoid, aquantity of the imprinting material from extending beyond the region ofsurface 36 in superimposition with patterned mold 26, while obtainingdesired thicknesses t₁ and t₂, i.e., through capillary attraction of theimprinting material with patterned mold 26 and surface 36 and surfaceadhesion of the imprinting material.

Referring to FIG. 2, after a desired distance “d” has been reached,radiation source 22 produces actinic radiation that polymerizes andcross-links the imprinting material, forming solidified imprinting layer134. The composition of imprinting layer 34 transforms from a fluidicimprinting material to a solidified material. This provides solidifiedimprinting layer 134 with a side having a shape that conforms to a shapeof a surface 50 of patterned mold 26, shown more clearly in FIG. 5. As aresult, solidified imprinting layer 134 is formed having recessions 52and protrusions 54. After formation of solidified imprinting layer 134,distance “d” is increased so that patterned mold 26 and solidifiedimprinting layer 134 are spaced-apart. Typically, this process isrepeated several times to pattern different regions (not shown) ofsubstrate 32, referred to as a step and repeat process. An exemplarystep and repeat process is disclosed in published U.S. patentapplication Ser. No. 2004/0008334, filed Jul. 11, 2002 as applicationSer. No. 10/194,414, entitled “Step and Repeat Imprint Lithography,”which is assigned to the assignee of the present invention and isincorporated herein by reference.

The advantages of this patterning process are manifold For example, thethickness differential between protrusions 54 and recessions 52facilitates formation, in substrate 32, of a pattern corresponding tothe pattern in solidified imprinting layer 134. Specifically, thethickness differential between t₁ and t₂ of protrusions 54 andrecessions 52, respectively, results in a greater amount of etch timebeing required before exposing regions of substrate 32 insuperimposition with protrusions 54 compared with the time required forregions of substrate 32 in superimposition with recessions 52 beingexposed. For a given etching process, therefore, etching will commencesooner in regions of substrate 32 in superimposition with recessions 52than regions in superimposition with protrusions 54. This facilitatesformation of a pattern in substrate 32 corresponding to the pattern insolidified imprinting layer 34. By properly selecting the imprintingmaterials and etch chemistries, the relational dimensions between thediffering features of the pattern eventually transferred into substrate32 may be controlled as desired. To that end, it is desired that theetch characteristics of solidified imprinting layer 134, for a givenetch chemistry, be substantially uniform.

As a result, the characteristics of the imprinting material areimportant to efficiently pattern substrate 32 in light of the uniquepatterning process employed. As mentioned above, the imprinting materialis deposited on substrate 32 as a plurality of discrete and spaced-apartdroplets 38. The combined volume of droplets 38 is such that theimprinting material is distributed appropriately over an area of surface36 where imprinting layer 34 is to be formed. In this fashion, the totalvolume of the imprinting material in droplets 38 defines the distance“d”, to be obtained so that the total volume occupied by the imprintingmaterial in the gap defined between patterned mold 26 and the portion ofsubstrate 32 in superimposition therewith once the desired distance “d”is reached is substantially equal to the total volume of the imprintingmaterial in droplets 38. As a result, imprinting layer 34 is spread andpatterned concurrently, with the pattern being subsequently set byexposure to the actinic radiation. To facilitate the deposition process,it is desired that the imprinting material provide rapid and evenspreading of the imprinting material in droplets 38 over surface 36 sothat all thicknesses t₁ are substantially uniform and all residualthicknesses t₂ are substantially uniform.

An exemplary composition for the imprinting material consists of thefollowing:

COMPOSITION 1 isobornyl acrylateacryloxymethylbis(trimethylsiloxy)methylsilane ethylene glycoldiacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one COMPOSITION 2isobornyl acrylate acryloxymethyltris(trimethylsiloxy)silane ethyleneglycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one COMPOSITION 3isobornyl acrylate 3-acryloxypropylbis(trimethylsiloxy)methylsilaneethylene glycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-oneCOMPOSITION 4 isobornyl acrylate3-acryloxypropyltris(trimethylsiloxy)silane ethylene glycol diacrylate2-hydroxy-2-methyl-1-phenyl-propan-1-one COMPOSITION 5 isobornylacrylate acryloxymethylbis(trimethylsiloxy)methylsilane ethylene glycoldiacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one R₁R₂ COMPOSITION 6isobornyl acrylate acryloxymethyltris(trimethylsiloxy)silane ethyleneglycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one R₁R₂COMPOSITION 7 isobornyl acrylate3-acryloxypropylbis(trimethylsiloxy)methylsilane ethylene glycoldiacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one R₁R₂ COMPOSITION 8isobornyl acrylate 3-acryloxypropyltris(trimethylsiloxy)silane ethyleneglycol diacrylate 2-hydroxy-2-methyl-1-phenyl-propan-1-one R₁R₂

In COMPOSITIONs 1, 2, 3 and 4, the first silicon-free acrylate,isobornyl acrylate, comprises approximately 42% of the composition, butthe quantity present therein may range from 20-60%. Thesilicon-containing acrylate comprises approximately 37% of either ofCOMPOSITIONs 1, 2, 3 and 4, but the quantity present therein may rangefrom 30-50%. The second silicon-free acrylate, cross-linker ethyleneglycol diacrylate, comprises approximately 18% of either of COMPOSITIONs1, 2, 3 and 4, but the quantity present may range from 10% to 40%. Theinitiator, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, comprisesapproximately 0.5% to 5% and is responsive to UV radiation to facilitatecross-linkable and polymerization of COMPOSITIONs 1-4. For improvedrelease characteristics, COMPOSITIONs 5, 6, 7 and 8, in addition to thecomponents of COMPOSITIONs 1-4, each includes the surfactant R₁R₂ tocomprise approximately 0.5% of the composition. The remaining componentsof COMPOSITIONS 5, 6, 7, and 8 are reduced proportionally to compensatefor the addition of the surfactant. For purposes of this invention asurfactant is defined as any molecule, one tail of which is hydrophobic.Surfactants may be either fluorine-containing, e.g., include a fluorinechain, or may not include any fluorine in the surfactant moleculestructure.

An exemplary surfactant is available under the trade name ZONYL® FSO-100from DUPONT™ that has a general structure of R₁R₂, whereR₁=F(CF₂CF₂)_(Y) with y being in a range of 1 to 7, inclusive, andR₂=CH₂CH₂O(CH₂CH₂O)_(X)H where X is in a range of 0 to 15, inclusive Itshould be understood, however, that other surfactants may be included inCOMPOSITIONs, 5, 6, 7 and 8 in lieu of theF(CF₂CF₂)_(Y)CH₂CH₂O(CH₂CH₂O)_(X)H surfactant or in addition thereto.Additional surfactants may include fluorinated polymeric surfactantsavailable from 3M Company under the designations FLUORAD® FC4432 and/orFLUORAD® FC4430. In addition, other UV photo-initiators may be employedin conjunction with or in lieu of2-hydroxy-2-methyl-1-phenyl-propan-1-one. It should be understood thatnon-photo-initiators may be employed such as thermal initiators. As aresult, the actinic radiation employed to facilitate cross-linkable andpolymerization would be thermal in nature, e.g., infrared radiation.

Referring to FIG. 4, an exemplary method of forming solidifiedimprinting layer 134 includes depositing a plurality of droplets in apattern 100 to minimize trapping of gases when spreading the imprintingmaterial over surface 36. To that end, pattern 100 is formed from aplurality of droplets 101-149 that are deposited sequentially, in theorder number with droplet 101 being dispensed first and droplet 149being dispensed last. It was found, however, that etch characteristicsof the solidified imprinting layer 134 differed as a function of theposition of the droplet in the drop dispense sequence, referred to assequential etch differential (SED).

It was determined that the SED is attributable to variations, over thearea of solidified imprinting layer 134, of the cross-linked andpolymerized components that form solidified imprinting layer 134. Thecomponent variation in solidified imprinting layer 134 was found tooccur while the imprinting material is in a fluidic state, due toevaporation. Specifically, it was discovered that the composition of theimprinting material changed before the same was polymerized andcross-linked. During the imprinting process evaporation may occur duringseveral intervals of time. An interval of time between dispensing ofdroplet 101 and contact of pattern 100 with mold 26 may be on the orderof 20 seconds. This is believed to be the interval during which thegreatest evaporation occurs. During this interval evaporation of theimprinting material occurs with the loss of the imprinting materialbeing proportional to the length of the interval between deposition andcontact with mold 26. After contact with mold 26 a second interval oftime is required to spread droplets 101-149 and form a contiguoussilicon-containing layer on substrate 32. During the second interval oftime, typically on the order of ten seconds, additional evaporation ofthe imprinting material occurs.

The present invention overcomes SED by ensuring that specifiedpolymerizable components are present in solidified imprinting layer 134in a desired quantity. In the present example, the desirablepolymerizable components are the silicon-containing acrylate componentand the non-silicon containing/silicon-free acrylate component thatincludes IBOA and the cross-linker component, EDGA, all of which areacrylates. Specifically, it is recognized that the non-uniformity of theetch characteristics of solidified imprinting layer 134 is due tovariations of the silicon content over the area thereof.

Prior art silicon-containing compositions in which thesilicon-containing acrylate evaporated faster than the remainingcomponents of the composition were found to present etch non-uniformity.This is seen examining FIGS. 5 and 6. In FIG. 5 a silicon-containinglayer 150 formed from the aforementioned prior art silicon-containingcomposition appears substantially smooth and uniform in topography.After subjecting layer 150 to a plasma etch process, non-uniformity canbe observed by the myriad of recessed regions 152 appearing in etchedlayer 154. This results from the faster etch rate associated withrecessed regions 152, compared to the etch rates of projecting regions156. It is believed that the faster etch rates of recessed regions 152result from a lower amount of silicon present, compared with thesilicon-content of projecting regions 156. The non-uniformity ofsilicon-containing content in layer 150 results in uneven etching ofetched layer 152, which is undesirable.

The present invention attenuates, if not avoids, etch non-uniformity ina silicon-containing layer by configuring compositions for imprintingmaterial in which the desirable components have desired rates ofevaporation during a desired interval of time. Although it is possibleto provide compositions in which the rate of evaporation of the desiredcomponents is substantially the same for an infinite period, this wasdetermined to be unnecessary. Rather, the polymerizable components ofCOMPOSITIONs 1-8 are selected so as to have a desired relative rate ofevaporation in the interval of time between deposition and exposure toactinic radiation. The remaining component, i.e., the photo-initiator,2-hydroxy-2-methyl-1-phenyl-propan-1-one, of COMPOSITIONs 1-4 is notconsidered a polymerizable component, although it becomes part of thepolymerized structure. Therefore, the photo-initiator,2-hydroxy-2-methyl-1-phenyl-propan-1-one does not contributesubstantially to the structural characteristics of the resultingimprinting layer, which minimizes the need to match the rate ofevaporation with the rate of evaporation of the acrylate components.Similarly, the remaining components, i.e., the photo-initiator,2-hydroxy-2-methyl-1-phenyl-propan-1-one, and the surfactant,R_(f)CH₂CH₂O (CH₂CH₂O)_(X)H of COMPOSITIONs 5-8 are not consideredpolymerizable components. Further, it is desired that thenon-polymerizable components of COMPOSITIONs 1-8 evaporate at a ratethat is slower than the rate of evaporation of the acrylate components.

Referring to FIG. 7, shown are various curves demonstrating the relativerate of evaporation for specified components in a 400 pL droplet ofCOMPOSITION 1, with the specified components being as follows: ethyleneglycol diacrylate (EDGA), acryloxymethylbis(trimethylsiloxy)methylsilane (AMBMS), and isobornyl acrylate (IBOA).The 400 pL droplet was formed by deposition of multiple droplets, eachhaving a volume of 80 pL, onto a common area to provide the 400 pLdroplet with a radius of approximately 82 microns. The relative rate ofevaporation between the components of COMPOSITION 1 is shown being lessthan 0.1%/second that translates to less than 2% for an interval of 20seconds and approximately 5% over an interval of 60 seconds. Similarrates of evaporation for the polymerizable components of COMPOSITIONs2-8 are also found. As a result, COMPOSITIONs 1-8 each possess desirablecharacteristics in that the polymerizable components thereof havesubstantially uniform rates of evaporation that provide a substantiallyuniform density of silicon over the volume of solidified imprintinglayer 134, shown in FIG. 3. Specifically, solidified imprinting layer134 was provided with a desired silicon content of no less than 8% byweight over the given area of solidified imprinting layer 134. A maximumvariation of the weight of the silicon content between any two regionsof solidified imprinting layer 134 should be no greater than 5%.

Additionally, COMPOSITIONs 1-8 provide a desirable viscosity that may bein a range of 1 to 20 centipoise, with less than 5 centipoise beingpreferable. This facilitates deposition employing droplet dispensetechniques. Also, COMPOSITIONs 1-8 provide solidified imprinting layer134 with a desired mechanical strength so that the break stress isgreater than or equal to 15 MPa.

Referring to FIGS. 2 and 8, it may be desirable to provide substrate 32with a smooth, if not planar, surface upon which to form imprintinglayer 34. To that end, substrate 32 may include a primer layer 96.Primer layer 96 has proved beneficial when surface 36 of substrate 32appears rough when compared to the features dimensions to be formed inimprinting layer 34. Primer layer 96 may also function, inter alia, toprovide a standard interface with imprinting layer 34, thereby reducingthe need to customize each process to the imprinting material from whichsubstrate 32 is formed. In addition, primer layer 96 may be formed froman organic imprinting material with the same or different etchcharacteristics as imprinting layer 34. As a result, primer layer 96 isfabricated in such a manner so as to possess a continuous, smooth,relatively defect-free surface that may exhibit excellent adhesion toimprinting layer 34. An exemplary material to use to form primer layer96 is available from Brewer Science, Inc. of Rolla Mo. under the tradename DUV30J-6. The primer layer 96 is typically provided with athickness to facilitate providing the desired surface profile andwithout being opaque to optical sensing equipment employed to detectpatterns, such as alignment marks, on substrate 32 surface.

Referring to FIGS. 8 and 9, it has been found beneficial to deposit aprimer layer 196 when an imprinting layer 34 is present upon a surface136 of substrate 32 that has been previously patterned. To that end,primer layer 196, as with primer layer 96, may be deposited employingany known deposition method, including droplet dispense techniques,spin-on techniques and the like. Furthermore, to enhance the smoothnessof the surface of either of primer layer 96 and 196, it may be desiredto contact the same with a planarization mold 80 having a substantiallysmooth, if not planar, contact surface.

To reduce the probability that solidified primer layers 96 and 196adhere to planarization mold 80, the same may be treated with a lowsurface energy coating 98. Low surface energy coating 98 may be appliedusing any known process. For example, processing techniques may includechemical vapor deposition method, physical vapor deposition, atomiclayer deposition or various other techniques, brazing and the like. In asimilar fashion a low surface energy coating (not shown) may be appliedto mold 26, shown in FIG. 2.

In addition to the aforementioned surfactants and low surface energycoatings, fluorinated additives may be employed to improve releaseproperties of the imprinting material. Fluorinated additives, likesurfactants, have a surface energy associated therewith that is lowerthan a surface energy of the imprinting material. An exemplary processby which to employ the aforementioned fluorinated additive is discussedby Bender et al. in MULTIPLE IMPRINTING IN UV-BASED NANOIMPRINTLITHOGRAPHY: RELATED MATERIAL ISSUES, Microelectronic Engineering pp.61-62 (2002). The low surface energy of the additive provides thedesired release properties to reduce adherence of cross-linked andpolymerized imprinting material molds 26 and 80. It should be understoodthat the surfactant may be used in conjunction with, or in lieu of,COMPOSITIONs 5-8 that include a surfactant.

Referring to FIGS. 5 and 10, it should be understood that the benefitsprovided by the present invention apply equally to layers formedemploying other techniques where evaporation may occur during the layerformation. Exemplary deposition techniques that may be employed to formsolidified layer 134 include spin-on techniques, laser assisted directimprinting (LADI) techniques and the like. An exemplary LADI techniqueis disclosed by Chou et al. in “Ultrafast and Direct Imprint ofNanostructures in Silicon,” Nature, Col. 417, pp. 835-837, June 2002.For example, employing a spin-on technique, any one of COMPOSITIONs 1-8may be deposited on substrate 32 as layer 234. Thereafter, layer 234 maybe patterned by employing mold 26. The benefits of the present inventionbecome salient, were layer 234 to be patterned employing step and repeattechniques, during which differing regions of layer 234 would bepatterned and subsequently solidified, sequentially.

The embodiments of the present invention described above are exemplary.Many changes and modifications may be made to the disclosure recitedabove, while remaining within the scope of the invention. For example,the ratio of the components of each of the aforementioned COMPOSITIONsmay be varied. Additionally, while the invention has been discussed withrespect to controlling the silicon content in a layer to improve etchuniformity, the present invention may apply equally well, to improvingother characteristics of a layer, such as adhesion, preferential or not,stress, thickness uniformity, roughness, strength, density and the like.The scope of the invention should, therefore, not be limited by theabove description, but instead should be determined with reference tothe appended claims along with their full scope of equivalents.

1. A composition comprising: a plurality of polymerizable components,including a silicon-containing polymerizable component and asilicon-free polymerizable component; and an initiator component tofacilitate a change of phase state of said plurality of polymerizablecomponents between a fluidic phase state and a solidified phase state,where said plurality of polymerizable components have a predeterminedrelative rate of evaporation less than 0.1% per second during apredetermined interval of time in a range of 0 to 20 seconds.
 2. Thecomposition as recited in claim 1 wherein said plurality includes all ofsaid plurality of polymerizable components.
 3. The composition asrecited in claim 1 wherein each of said plurality of polymerizablecomponents has a similar rate of evaporation within a predeterminedrange during a predetermined interval of time.
 4. The composition asrecited in claim 1 wherein said plurality of polymerizable componentshas a rate of evaporation within a predetermined range during aninterval of time in a range of 10 to 20 seconds, inclusive.
 5. Thecomposition as recited in claim 1 wherein said composition has aviscosity associated therewith to facilitate formation of droplets upona substrate having a volume associated therewith of at least 80 pL. 6.The composition as recited in claim 1 wherein said composition has aviscosity associated to facilitate deposition upon a substrate employingspincoating processes.
 7. The composition as recited in claim 1 whereinsaid silicon-containing polymerizable component includesacryloxymethylbis(trimethylsiloxy)methylsilane and said silicon-freepolymerizable component includes isobornyl acrylate.
 8. The compositionas recited in claim 1 wherein said silicon-containing polymerizablecomponent includes acryloxymethyltris(trimethylsiloxy)silane and saidsilicon-free polymerizable component includes isobornyl acrylate.
 9. Thecomposition as recited in claim 1 wherein said silicon-containingpolymerizable component includes 3-acryloxypropylbis(trimethylsiloxy)methylsilane and said silicon-free component includes isobornylacrylate.
 10. The composition as recited in claim 1 wherein saidsilicon-containing polymerizable component includes3-acryloxypropyltris(trimethylsiloxy)silane molecules and saidsilicon-free polymerizable component includes isobornyl acrylate. 11.The composition as recited in claim 1 wherein said silicon-freepolymerizable component includes a cross-linker component.
 12. Thecomposition as recited in claim 1 wherein said initiator componentincludes 2-hydroxy-2-methyl-1-phenyl-propan-1-one.
 13. The compositionas recited in claim 1 further including a surfactant.
 14. Thecomposition as recited in claim 1 wherein said silicon-freepolymerizable component further includes first and secondsub-components, with said first sub-component being a cross-linkercomponent, with said cross-linker component consisting of approximately10%-40% of said composition, and said second sub-component consisting ofapproximately 20% to 60% of said composition and said silicon-containingcomponent consisting of approximately 30% to 50% of said composition.15. A composition comprising: a plurality of acrylate components,including a silicon-containing acrylate component and a firstsilicon-free acrylate component and a second silicon-free acrylatecomponent; and an initiator component to facilitate a change of phasestate of said plurality of acrylate components between liquefied phasestate and a solidified phase state, with each of said plurality ofacrylate components having a predetermined relative rate of evaporationless than 0.1% per second during a predetermined interval of time in arange of 0 to 20 seconds.
 16. The composition as recited in claim 15wherein said composition has a viscosity associated therewith tofacilitate formation of droplets upon a substrate having a volumeassociated as small as 80 pL.
 17. The composition as recited in claim 15wherein said composition has a viscosity associated to facilitatedeposition upon a substrate employing spincoating processes.
 18. Thecomposition as recited in claim 15 wherein said silicon-containingacrylate component comprises 30% to 50% of said composition and includesacryloxymethylbis(trimethylsiloxy)methylsilane and said firstsilicon-free acrylate component comprises 20% to 60% of said compositionand includes isobornyl acrylate and said second silicon-free acrylatecomponents comprises 10% to 40% of said composition and includesethylene glycol diacrylate.
 19. The composition as recited in claim 15wherein said silicon-containing acrylate component comprises 30% to 50%of said composition and includesacryloxymethyltris(trimethylsiloxy)silane and said first silicon-freeacrylate component comprises 20% to 60% of said composition and includesisobornyl acrylate and said second silicon-free acrylate componentscomprises 10% to 40% of said composition and includes ethylene glycoldiacrylate.
 20. The composition as recited in claim 15 wherein saidsilicon-containing acrylate component comprises 30% to 50% of saidcomposition and includes3-acryloxypropylbis(trimethylsiloxy)methylsilane and said firstsilicon-free acrylate component comprises 20% to 60% of said compositionand includes isobornyl acrylate and said second silicon-free acrylatecomponents comprises 10% to 40% of said composition and includesethylene glycol diacrylate.
 21. The composition as recited in claim 15wherein said silicon-containing acrylate component comprises 30% to 50%of said composition and includes 3acryloxypropyltris(trimethylsiloxy)silane and said first silicon-freeacrylate component comprises 20% to 60% of said composition and includesisobornyl acrylate and said second silicon-free acrylate componentscomprises 10% to 40% of said composition and includes ethylene glycoldiacrylate.
 22. The composition as recited in claim 15 wherein saidsilicon-free acrylate component includes a cross-linker component. 23.The composition as recited in claim 15 wherein said initiator componentincludes 2-hydroxy-2-methyl-1-phenyl-propan-1-one.
 24. A compositioncomprising: an isobornyl acrylate component; an ethylene glycoldiacrylate component; a photo-initiator component; and asilicon-containing acrylate component selected from a set of componentsconsisting essentially ofacryloxymethylbis(trimethylsiloxy)methylsilane,acryloxymethyltris(trimethylsiloxy)silane and3-acryloxypropylbis(trimethylsiloxy)methylsilane where saidpolymerizable components have a predetermined rate of evaporation lessthan 0.1% per second during a predetermined interval of time in a rangeof 0 to 20 seconds.
 25. The composition as recited in claim 24 whereineach of isobornyl acrylate component, said silicon-containing component,said ethylene glycol diacrylate component have a predetermined relativerate of evaporation associated therewith.
 26. The composition as recitedin claim 24 wherein said silicon-containing acrylate component comprises30% to 50% of said composition isobornyl acrylate component comprises20% to 60% of said composition and said ethylene glycol diacrylatecomponent comprises 10% to 40% of said composition.
 27. The compositionas recited in claim 26 further including a surfactant.
 28. Thecomposition recited in claim 27 wherein said surfactant comprisesapproximately 0.5% to 2% of said composition and includes a fluorinatedpolymeric surfactant.
 29. A composition comprising: an isobornylacrylate component; an ethylene glycol diacrylate component; and aphoto-initiator component; and a silicon-containing acrylate componentconsisting essentially of 3-acryloxypropyltris(trimethylsiloxy)silanewhere said polymerizable components have a predetermined rate ofevaporation less than 0.1% per second during a predetermined interval oftime in a range of 0 to 20 seconds.